1. Field of the Invention
The present invention relates to a preparation method of a tube, which includes modifying the inner surface of a tube using plasma; a preparation method of a tube, which includes preparing a tube, modifying the inner surface of the tube using microplasma so as to have reactivity, forming a thin film layer on the modified surface of the tube to prevent aging or impart adhesiveness, and modifying the surface of the thin film layer using microplasma so as to enhance cell adhesion thereon; and a transplantable polymer tube prepared by the above method.
2. Description of the Related Art
Vascular diseases are caused by a hardening of the arteries due to a thickening of the inside of the arteries mainly as a result of fat accumulation or plaque (or atheroma). The arteries are blood vessels that supply blood, oxygen and nutrients to the whole body from the heart. Thus, the narrowed and hardened arteries disturb the flow of blood and make it difficult to efficiently supply the above materials to individual organs. Such an insufficient supply of blood incurs dysfunction, tissue damage, etc., and in severe cases, leads to death. Hence, in order to treat vascular diseases, drugs which relax blood vessels are administered, but drug treatment merely mitigates symptoms and does not cure vascular diseases, and may thus result in lifelong drug dependence, which is undesirable. Other treatment methods may include surgical methods in which a damaged blood vessel is removed and an artificial blood vessel is transplanted into the corresponding portion.
Although methods of transplanting arteries or veins of donors have been initially implemented, they suffer from low success rates due to rejection or sclerosis. Hence, research and development into synthetic (artificial) blood vessels has been conducted. Artificial blood vessels for transplantation have to be made of materials which are harmless to the human body and have high biocompatibility. Furthermore, these materials should not be rejected by the immune system and should be able to be maintained for a long time in vivo. Also, there should be no cases in which blood vessels are clogged by precipitation of proteins or lipids or due to thrombosis.
Typically, polymer materials, which are very stable in vivo, are being utilized as biomaterials in terms of artificial blood vessels, artificial hearts, alternatives to metal stents, etc. Among these, polymer tubes are variously applied for use as hemodialysis tubes, human circulatory system transplantation tubes, tubes for diagnostic bio-kits, syringes, etc. The polymer tubes are surface-modified depending on end use, and such surface modification is mainly performed only on the outer surface. Examples of the methods for surface treatment include electron beam treatment, ion beam treatment, coating methods, wet methods, etc. using vacuum techniques and plasma. This surface modification enables the polymer material to be changed to have a reactive coupling structure of the surface which is different from a reactive coupling structure of the bulk polymer material which is the unmodified portion.
Surface modification techniques for a biologically reactive outer surface include surface modification of human circulatory system transplantation tubes using a wet method as disclosed in Korean Patent Nos. 10-1034654, 10-1119011 and 10-1161151, and modification of a fluorinated polymer into a superhydrophobic surface using vacuum plasma as disclosed in Korean Patent No. 10-1185835.
Meanwhile, as biomaterials to be transplanted in vivo, the inner surface of polymers preferably has to have thrombotic resistance and/or inflammation inhibitory ability in order to prevent clogging due to thrombosis and inflammation. Also, the outer surface thereof should have high compatibility with the peripheral cells, and should be able to inhibit protein reactions and inflammation. In the case where typical fluorinated polymers, which are hydrophobic and inert without reactivity to materials having different characteristics, are provided in the form of a tube, both the inner and outer surfaces thereof are inert and hydrophobic. Thus, the inert and hydrophobic polymers may be imparted with hydrophilicity using the above surface modification techniques or may be deposited with biomaterials having increased reactivity, so that such polymers may be modified into materials suitable for human transplantation.
To typically impart superhydrophobicity onto the surface of a material, the corresponding processes have been developed using conventional surface treatment methods for drugs. However, such surface modification methods mostly include modification of the outer surface of tubes, and techniques for modifying the inner surface thereof are very limited.